4.5-rc4: pool: segfault, systemd-udevd blocked for more than 120 seconds

[Pavel Machek]

Hi!

I realized ttyUSB0 is no longer detected, then I found this in the
logs:

[25428.048405] r8169 0000:03:00.0 eth0: link up
[27996.669945] sd 4:0:0:0: [sdc] 7744512 512-byte logical blocks:
(3.97 GB/3.69
GiB)
[27996.686679]  sdc: sdc1 sdc2 sdc3 sdc4
[27997.850843] pool[3086]: segfault at 0 ip 000000000807ab34 sp
00000000f42fbbf0
 error 4 in udisksd[8048000+62000]
 [29280.148056] INFO: task systemd-udevd:2094 blocked for more than
 120 seconds.
 [29280.148061]       Not tainted 4.5.0-rc4 #37
 [29280.148063] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
 disables this message.
 [29280.148065] systemd-udevd   D ffff8800b7d0fb30     0  2094      1
 0x20020000
 [29280.148071]  ffff8800b7d0fb30 ffff880000000001 0000000000000000
 ffff8800b891c1c0
 [29280.148077]  ffff8800b891c960 0000000000000292 ffff8800b7d10000
 ffff8800b5fe8b20
 [29280.148081]  ffff8800b891c1c0 00000000ffffffff 0000000000000246
 ffff8800b7d0fb48
 [29280.148086] Call Trace:
 [29280.148095]  [<ffffffff8494e050>] schedule+0x30/0x80
 [29280.148099]  [<ffffffff8494e319>]
 schedule_preempt_disabled+0x9/0x10
 [29280.148102]  [<ffffffff8494fac5>] mutex_lock_nested+0x105/0x2e0
 [29280.148106]  [<ffffffff8414f9f1>] ? __blkdev_get+0x41/0x3f0
 [29280.148110]  [<ffffffff842d90af>] ? disk_block_events+0x5f/0x80
 [29280.148113]  [<ffffffff8414f9f1>] __blkdev_get+0x41/0x3f0
 [29280.148116]  [<ffffffff8414fddc>] blkdev_get+0x3c/0x390
 [29280.148119]  [<ffffffff84951f62>] ? _raw_spin_unlock+0x22/0x30
 [29280.148122]  [<ffffffff84150180>] ? blkdev_get_by_dev+0x50/0x50
 [29280.148125]  [<ffffffff841501d6>] blkdev_open+0x56/0x70
 [29280.148129]  [<ffffffff8411abf9>]
 do_dentry_open.isra.16+0x149/0x2d0
 [29280.148132]  [<ffffffff8411b9dd>] vfs_open+0x4d/0x50
 [29280.148135]  [<ffffffff8412a81a>] path_openat+0x47a/0xf80
 [29280.148139]  [<ffffffff8412c199>] do_filp_open+0x79/0xd0
 [29280.148143]  [<ffffffff84138b57>] ? __alloc_fd+0xb7/0x170
 [29280.148146]  [<ffffffff84951f62>] ? _raw_spin_unlock+0x22/0x30
 [29280.148148]  [<ffffffff84138b57>] ? __alloc_fd+0xb7/0x170
 [29280.148151]  [<ffffffff8411bd05>] do_sys_open+0x115/0x1e0
 [29280.148155]  [<ffffffff841655d6>] compat_SyS_open+0x16/0x20
 [29280.148159]  [<ffffffff8400241e>] do_syscall_32_irqs_off+0x4e/0xa0
 [29280.148163]  [<ffffffff8495413a>] entry_INT80_compat+0x2a/0x40
 [29280.148166] 1 lock held by systemd-udevd/2094:
 [29280.148167]  #0:  (&bdev->bd_mutex){......}, at:
 [<ffffffff8414f9f1>] __blkdev_get+0x41/0x3f0
 [29322.817302]  sdc: sdc1 sdc2 sdc3 sdc4
 [39510.918856] liferea[12340]: segfault at c ip 00000000080862ad sp
 00000000fff5acd8 error 4 in liferea[8048000+89000]
 [43259.795891] nf_conntrack: automatic helper assignment is
 deprecated and it will be removed soon. Use the iptables CT target to
 attach helpers instead.
 [49435.300297] PM: Syncing filesystems ... done.
 [49435.403970] PM: Preparing system for sleep (mem)
 [49435.404385] Freezing user space processes ... (elapsed 0.039
 seconds) done.
 [49435.444222] Freezing remaining freezable tasks ... (elapsed 0.004
 seconds) done.

I'll try to update to newer -rc, and see if it happens again, but if
you have some other hints, let me know.

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html